Research Description

The connection between CO2 emission from fossil fuel combustion and global warming has been the focal point of discussion in recent years. Meanwhile, particular matter and hazardous gas emissions from transportation vehicles, stationary power plants, and heating and cooling systems are largely responsible for the unhealthy air quality of many mega cities. These grand challenges of the global society have to be addressed by aggressively pursuing both cleaner fossil fuel utilization technologies and a paradigm shift to renewable energy sources such as solar and wind, clean transportation approaches including electric vehicles, and efficient energy utilization technologies.

The goal of our research is to make significant advances in select areas of sciences and technologies that enable sustainable use of energy and improve the quality of life. Our current research is focused on the following topics:

  1. Ultrahigh thermal conductivity materials
  2. Two-dimensional materials and devices
  3. Thermoelectric materials and devices
  4. Spin caloritronics

Because over 90% of the global energy use relies on thermal processes, one important objective of our current and future research efforts is to discover and invent materials, devices, and systems for sustainable thermal energy utilization, in order to make broad societal impacts in several technological areas including:

  1. Energy efficiency and thermal management of electronic devices, which turn about 10% of US electricity budget into heat flux as high as those found in nuclear reactors;
  2. Recovery of waste heat, which amounts to over 60% of fuel energy consumption of transportation vehicles and between 20 to 50% of industrial energy input;
  3. Efficient heating and cooling of buildings and vehicles, which consumes as much as 20% of US energy supply;
  4. Concentrated solar thermal power, which is receiving renewed interest because thermal energy storage is employed to address the intermittency of solar flux.

Compared to photovoltaic and electrochemical energy systems where continuous progresses have been made through innovations in materials and devices, thermal energy systems have predominantly relied on legacy technologies. We seek to break the current limits of these legacy technologies, especially along the following directions:

  1. In existing and emerging electronic, optoelectronic, and photovoltaic devices, the limited electron and thermal transport properties of semiconducting, metallic, dielectric, and polymeric materials result in high heat dissipation densities and local hot spots. Novel materials with ultrahigh electron mobility and thermal conductivity can significantly enhance the energy efficiency, performance, and thermomechanical reliability of these solid-state electronic and energy devices. Meanwhile, materials with ultralow thermal conductivity can enable efficient solid-state thermoelectric devices, low-energy loss windows for buildings, and many other applications.        
  2. For waste heat recovery, rapid progresses have been made to increase the figure of merit (ZT) of PbTe and Bi2Te3 materials for solid-state thermoelectric energy conversion based on the Seebeck and Peltier effects. However, these materials contain either rare or toxic elements. If the ZT of other non-toxic materials made of earth-abundant elements can be enhanced to exceed the state of the art, or other novel and efficient thermal-to-electric conversion mechanisms can be discovered, it may enable widespread use of compact, efficient, and reliable solid-state thermoelectric devices for vehicle waste heat recovery at a scale commensurate to the global vehicle manufacturing enterprise.
  3. For thermal energy storage, the energy density and power capacity are limited by the low latent heat and thermal conductivity values of existing storage media, such as molten salts, ice, and paraffin wax. Novel thermal storage materials and devices with enhanced energy density and power capacity can lower the cost of large-capacity concentrated solar power plants, drastically increase the use of roof-top solar thermal systems, and enable compact heating and cooling devices for thermal management of buildings, electric vehicles, electronic devices, electrochemical energy storage systems, and concentrated photovoltaic systems.
  4. In concentrated solar thermal power systems, the exergy efficiency can be increased considerably by increasing the thermal receiver temperature if thermally stable solar absorption coating materials and heat transfer fluids can be developed, or a high-efficiency solid-state thermoelectric or thermionic topping cycle can be integrated.

In our research group, fundamental studies are carried out to discover materials with extraordinary properties and invent new approaches for energy-efficient solid-state electronic and energy devices, thermoelectric waste heat recovery, thermal energy storage, thermal management, and concentrated solar thermal power. The common theme of these multidisciplinary investigations is to understand and control the transport, conversion, and storage of energy from the macroscale down to the nanoscopic level of energy carriers, including molecules, electrons, phonons, photons, and magnons. The knowledge and expertise gained from these studies are further employed to explore novel sensor devices and new approaches for drug delivery and biomedical imaging. These efforts involve both thermal-fluid physics and materials science, as illustrated in our current and past projects listed below:

Hydrodynamic Thermal Transport in Graphitic Materials
Graduate Student Researchers: Eric Ou, Sean Sullivan, Evan Fleming, Jihoon Jeong
Collaboration: Prof. Yaguo Wang, Prof. Sangyeop Lee (University of Pittsburgh) 
Sponsor: National Science Foundation
Period: 08/2017-07/2020
Innovative Processes for Fabricating Three-Dimensional Ultrathin Foams with Enhanced Thermal Properties
Graduate Student Researchers: Evan Fleming, Eric Ou, Sally Jia
Collaboration: Prof. Donglei Fan
Sponsor: National Science Foundation
Period: 09/2016-08/2019
Energy Carrier Transport in Functionalized Two-Dimensional Layered Chalcogenides
Graduate Student and Post-doctoral Researchers: Hwijong Lee, Dr. Mir Mohammad Sadeghi
Collaboration: Prof. Steve Cronin (USC)
Sponsor: Department of Energy Office of Science
Period: 06/2016-05/2019
Ultrahigh Thermal Conductivity Materials
Graduate Student Researchers: Sean Sullivan, Yuanyuan Zhou, Dr. Jaehyun Kim 
Collaboration: Profs. David Broido (Boston College), David Cahill & Pinshane Huang (UIUC), Gang Chen (MIT), Ni Ni (UCLA), Zhifeng Ren (University of Houston), Bing Lv (University of Texas at Dallas), Jianshi Zhou (UT Austin) 
Sponsor: Office of Naval Research MURI Program
Period: 06/2016-05/2021
Graphitic Coatings and Porous Networks for Vehicle Thermal Management
Graduate Student and Post-doctoral Researchers: Evan Fleming, Dr. Iskandar Kholmanov
Period: 04/2016-03/2017
Probing Thermal Transport in Three-Dimensional Pillared Graphene Structures
Graduate Student and Post-doctoral Researchers: Evan Fleming, Dr. Iskandar Kholmanov
Collaboration: Profs. Liming Dai (CWRU), Dr. XiuLin Ruan (Purdue), Dr. Ajit Roy (ARFL)
Sponsor: Airforce Office of Scientific Research MURI/Case Western Reserve University
Period: 09/2015-11/2017
EFRI 2-DARE: Enhancing Electronic and Thermal Properties in Epitopotaxial Ge/Sn Graphane Heterostructures
Graduate Student Researcher: Gabriella Coloyan, Devika Mehta
Collaboration: Profs. Joshua Goldberger (OSU), David Broido (Boston College), David Cahill (UIUC), Joseph Heremans (OSU)
Sponsor: National Science Foundation
Period: 09/2014-08/2018
Development of Light Scattering Characterization Equipment for the Study of Magnon and Phonon Dynamics in Materials with Spin/Heat Coupling
Collaboration: Prof. Elaine Li (UT Austin)
Sponsor: Army Research Office Defense University Research Instrumentation Program (DURIP)
Period: 06/2014-06/2015
Size-dependent Phonon Transport in Boron Arsenide with Potentially Record-high Thermal Conductivity
 Post-doctoral & Graduate Student Researchers: JaeHyun Kim, Dan Evans, Owen Williams, Dr. Dan Sellan
Collaboration: Prof. Alan Cowley (UT Austin)
Sponsor: Office of Naval Research
Period: 06/2014-09/2017
Fully Integrated 2D Nanomaterials for High-Performance Flexible Nanoelectronics
Graduate Student Researcher: Brandon Smith
Collaboration: Prof. Deji Akinwande (UT Austin)
Sponsor: Office of Naval Research
Period: 01/2014-12/2017
Probing Highly Non-equilibrium Thermal Transport in Nanostructures and Devices
Graduate Student Researchers: Kevin Olsson, Sean Sullivan, Annie Weathers
Collaboration: Prof. Elaine Li (UT Austin)
Sponsor: National Science Foundation
Period: 09/2013-08/2017
Materials with Extraordinary Spin/Heat Coupling
Post-doctoral & Graduate Student Researchers:  Dr. Annie Weathers, Dr. Xi Chen, Sean Sullivan, Dr. Kyongmo An
Collaboration: Profs. Roberto Meyers, Joseph Heremans (Ohio State University), David Cahill (UIUC), David Awschalom (Univ of Chicago), Yaroslav Tserkovnyak (UCLA), Elaine Li (UT Austin), Jianshi Zhou (UT Austin) Sponsor: Army Research Office Multidisciplinary Uiversity Research Intitiative (MURI)
Period: 12/2013-12/2018
Phonon and Electron Transport in Pristine Two-Dimensional Layered Nanostructures and Heterostructures
Graduate Student Researchers: Gabriella Coloyan, Eric Ou
Collaboration: Prof. Steve Cronin (USC)
Sponsor: Department of Energy Office of Basic Energy Science
Period: 06/2013-05/2016
NSF Nanosystems Engineering Research Center: Nanomanufacturing Systems for Mobile Computing and Devices (NASCENT)
Graduate Student Researchers: Gabriella Coloyan, David Choi, Mir Mohammad Sadeghi
Collaboration: Profs. Deji Akinwande, Jayathi Murthy
Sponsor:National Science Foundation
Period: 09/2012-08/2022
MRI: Acquisition of a Spark Plasma Sintering System for Engineering Advanced Energy Materials and Materials Science Education
Collaboration: Profs. Jianshi Zhou, John Goodenough, Arumugam Manthiram, Desiderio Kovar (UT Austin)
Sponsor: National Science FoundationPeriod: 09/2012-06/2015
Thermal Batteries for Electric Vehicles
Post-doctoral & Graduate Student Researchers: Evan Fleming, Dr. Hengxing Ji, Dr. Abhijit Paul, Dr. Daniel Sellan, Dr. Shaoyi Wen, Dr. Eunsu Paek, Dr. Iskandar Kholmanov
Collaboration: Profs. Chris Bielawski, Alex da Silva, Rodney S. Ruoff, Jayathi Murthy, Gyeong Hwang, Dr. Peng Zhou, Dr. Dolf van der Heide
Sponsor: Department of Energy ARPA-E
Period: 11/2011-6/2015
Topological Insulator Coherent Energy Devices
Post-doctoral and Graduate Student Researchers: Dr. Michael Pettes, JaeHyun Kim
Sponsor: Defense Advanced Research Project Agency (DARPA) / Purdue University
Period: 06/2011-06/2015
High-Performance Thermoelectric Devices based on Abundant Silicide Materials for Vehicle Waste Heat Recovery
Graduate Student Researchers: Chad Baker, Xi Chen, Haiyan Fateh, Daniel Salta, Libin Zhang
Collaboration: Profs. J. B. Goodenough, M. J. Hall, J. S. Zhou (UT Austin), J. Song (University of Wisconsin-Madison)
Sponsor: National Science Foundation & Department of Energy Joint Thermoelectric Partnership
Period: 10/2010-05/2015
Energy Transport in Graphene
Graduate Student Researchers: Michael T. Pettes, Insun Jo, Mir Mohammad Sadeghi, Gabbi Coloyan
Collaboration: Prof. Steve Cronin (USC)
Sponsor: Department of Energy Office of Basic Energy Science
Period: 06/2010-05/2013
Ballistic and Quantum Thermal Transport Phenomena and Devices
Postdoctoral and Graduate Researchers: Dr. Jae Hun Seol, Dr. Arden Moore, JaeHyun Kim, Eric Ou
Sponsor: Office of Naval Research
Period: 02/2010-01/2013
High-Throughput Nanoimprint Fabrication of Shape-Specific, Stimuli-responsive Polymeric Nanocarriers for Drug and Imaging Agent Delivery
Graduate Student Researchers: Mary C. Moore, Vikramajit Singh, Patrick Jurney, Rachit Agarwal, Scott Marshall, David Choi
Collaboration: Prof. S.V. Sreenivasan (UT Austin), Prof. K. Roy (UT Austin), Dr. D. LaBrake (Molecular Imprint, Inc)
Sponsors: National Science Foundation
Period: 07/2009-09/2013
Electronic Thermal Transport in Nanoscale Conductors
Graduate Student Researchers: Mir Mohammad Sadeghi, Jae Hun Seol, Annie Weathers
Sponsor: National Science Foundation
Period: 07/2009-06/2013
Characterization of Nanostructured Thermoelectric Materials
Post-doctoral & Graduate Researchers: Dr. Arden Moore, Dr. Huijun Kong, Dr. Yong Lee, Dr. Michael Pettes, JaeHyun Kim
Sponsor: Office of Naval Research
Period: 07/2008-09/2011
Shape Specific, Enzyme-Responsive, Nano-Imprinted Particles for Drug Delivery
Graduate Student Researchers: Mary C. Moore, Rachit Agarwal, JaeHyun Kim
Collaboration: Prof. K. Roy (UT Austin)
Sponsors: National Institute of Health
Period: 07/2008-06/2011
Batch-Fabricated Nanowire Plasmonic Probes for Near Field Imaging of Single Molecules and Cells
Graduate Student Researcher: JaeHyun Kim
Post-doctoral Researcher: Dr. Yong Lee
Sponsor: Texas Higher Education Coordinating Board Norman Hackerman Advanced Research Program
Period: 05/2008-05/2010
Structure-Optical-Thermal Relationships of Carbon Nanotubes
Graduate Student Researchers: Michael T. Pettes, JaeHyun Kim
Collaboration: Prof. Steve Cronin (USC)
Sponsor: Department of Energy Office of Basic Energy Science
Period: 06/2007-05/2010
Catalyst Substrates with Nanoscale Features for Enhanced Reaction Activity
Graduate Student Researcher: Chad Baker
Collaboration: Prof. M. J. Hall (UT Austin)
Sponsor: Texas Hazardous Waste Research Center
Period: 09/2007-08/2010
High Temperature and Magnet Cryostats for Characterization of Nanowire and Thin Film Thermoelectric Materials
Sponsor: Office of Naval Research
Period: 05/2007-09/2008
Thermal Transport at Nanoscale Point and Line Constrictions and Interfaces
Graduate Student Researchers: Jae Hun Seol, Arden L. Moore, Nathan Malcolm, Sanjoy Saha
Collaboration: Prof. John R. Howell (UT Austin), Dr. Ravi S. Prasher (Intel)
Sponsor: National Science Foundation
Period: 09/2006-08/2010
NER: Nanoimprint Fabrication of Stimuli-responsive Drug Delivery Carriers
Graduate Student Researchers: Luz Cristal Glanchai, Mary C. Moore
Collaboration: Prof. K. Roy (UT Austin)
Sponsors: National Science Foundation
Period: 08/2006-07/2007
Room-Temperature Scanning Single-Electron-Transistor Microscopy of Nanoelectronic Devices
Gradate Student Researcher: Michael T. Pettes
Post-doctoral Researcher: Dr. Yong Lee
Collaboration: Prof. Zhen Yao (UT Austin)
Sponsor: Texas Higher Education Coordinating Board Norman Hackerman Advanced Research Program
Period: 08/2006-07/2008
Nanowire Composite Peltier Coolers
Graduate Student Researcher: Arden L. Moore
Sponsor: DARPA Advanced Processing and Prototyping Center (AP2C)
Period: 11/2005-11/2006
Investigation of Electrical Conductivity of Silicide and Copper Nanowires
Gradate Student Researcher: Bin Li
Collaboration: Prof. Paul S. Ho (UT Austin)
Sponsor: National Institute of Standards & Technology
Period: 06/2005-05/2006
Nanowire Composites for Energy Efficient Thermoelectric Refrigeration and Power Generation in Space Applications
Graduate Student Researchers: Feng Zhou, Jae Hun Seol
Collaborations: Dr. Laura Ye, Dr. Natalio Mingo, NASA Ames Research Center
Sponsor: NASA through Eloret Corporation
Period: 05/2005-05/2007
Directed Assembly of Metal Oxide Nanowires with Microsystems for Sensor Applications
Graduate Student Researcher: Choongho Yu Collaboration: Prof. Z. L. Wang (Georgia Institute of Technology) Sponsor: UT Research Grant Program Period: 09/2004-08/2005
Novel Nano and Micro-fabrication Methods for Injectable, Tissue-targeted, Stimuli-responsive Delivery Vehicles: Towards Simultaneous Delivery of Therapeutics and Contrast-agents
Graduate Student Researchers: Luz Cristal Glanchai, Mary C. Moore
Collaboration: Prof. K. Roy (UT Austin)
Sponsors: Charles W. Tate & Judy Spence Tate Charitable Foundation through UT Center for Biomedical Engineering
Period: 09/2004-08/2005
Nanoconductors for Future Interconnects and Air Bridge Interconnects
Graduate Student Researcher: Bin Li, Anastassios Mavrokefalos
Collaboration: Prof. Paul S. Ho, Zhen Yao, Rui Huang (UT Austin)
Sponsor: SEMATECH
Period: 09/2004-08/2006
YIP: Characterization of Nanostructures for Efficient Thermoelectric Refrigeration and Power Generation
Graduate Student Researchers: Anastassios Mavrokefalos, Feng Zhou
Sponsor: Office of Naval Research
Period: 06/2004-09/2008
Compact General-Purpose Bioagent Detector
Collaboration: Prof. Peter Gascoyne (UT MD Anderson Cancer Center), Prof. Shaochen Chen (UT Austin)
Sponsor: DOD Space and Naval Warfare Center
Period: 07/2003-06/2004
CAREER: Thermal Transport and Thermoelectric Measurements of Nanotransistors, Nanowires, and Superlattices
Graduate Student Researchers: Choongho Yu, Jianhua Zhou, Sanjoy Saha, Michael T. Pettes, Jae Hun Seol
Sponsor: National Science Foundation
Period: 03/2003-02/2008
Micro-flow Cytometers based on Dielectrophoretic Particle Focusing
Graduate Student Researcher: Choongho Yu
Collaboration: Prof. Peter Gascoyne (UT MD Anderson Cancer Center)
Sponsor: Whitaker Foundation through UT Center for Biomedical Engineering
Period: 09/2002-06/2003
Acquisition of a Scanning Probe Microscope and a Liquid Helium Cryostat for Nanoscale Thermal Science Research and Education at the University of Texas at Austin
Collaboration: Profs. Shaochen Chen and Zhen Yao (UT Austin)
Sponsor: National Science Foundation
Period: 06/2002-07/2004